Apple’s macOS High Sierra introduced enough performance enhancements that my dual-core, 2011 MacBook Air felt like it had new life breathed into it. Occasionally, though – and more and more frequently recently – events would cascade such that my CPU would run at full tilt for 5-10 minutes before finally settling in. When that was happening, Activity Monitor and/or iStat Menus would show two system processes chewing up CPU: tailspind and spindump. Thankfully, we now know how to stop that.